Use And Application Of ASTM Standard Guide For Estimation .

Use and Application ofASTM Standard Guidefor Estimation ofLNAPL Transmissivity(ASTM E2856-11)Christopher Pearson, P.E.AECOMDenver, COSeptember 17, 2013Client logo

Traditional Metric: In-wellLNAPL Thickness: Red Contours represent LNAPLwell Thickness (b) (ft) Green Contours representLNAPL Transmissivity (T)(ft 2/day)Characterization based on LNAPLThickness in wells can be dlyDecreasingWater TableClayASTM LNAPL Standard Guide forEstimating LNAPL TransmissivityClayLIF ResponseLIF ResponseLIF ResponseSandSandSeptember 17, 2013SandPage 2Client logo

MW-82: Groundwater and LNAPL Elevations Over TimeCorrected Groundwater Elevation (ft msl)509550905085508050751989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013Groundwater ElevationPresentationASTMLNAPL TitleStandard Guide forEstimating LNAPL TransmissivitySeptember 17, 2013September 17, 2013Product elevationPage 3Client logo

Why use LNAPL transmissivity? LNAPL transmissivity is a better metric for several reasons:– It can be estimated using recovery data or field testing on monitoring wells– Consistent across soil types– Consistent across confined, unconfined or perched conditions– Consistent for various LNAPL types– Is comparable for multiple sites and multiple technologies– It can be used for site characterization, mobility studies, technologyscreening and feasibility, recoverability modeling, remediation timeframes,performance monitoring, endpoints, and site-closureASTM LNAPL Standard Guide forEstimating LNAPL TransmissivitySeptember 17, 2013Page 4Client logo

1LNAPLTransmissivity:kroRelation of kro to LNAPLSaturationLNAPL Transmissivity (To): It is aproportionality coefficient describing theability of a formation to transmit LNAPL[L2/T]0 100%So0MW Zone of highest LNAPL saturationhas highest LNAPL conductivityLNAPL Low LNAPL saturation results in lowLNAPL conductivityTo Koover bo Hydraulic recovery rate proportionalto To for given technologyIn simple terms, To is the measure ofthe oil flow rate onto a well for aninduced gradient. So it is a directmeasure of LNAPL recoverabilitysince it incorporates time andconductivity.ASTM LNAPL Standard Guide forEstimating LNAPL TransmissivityKoog k krooKo(So) varies overshark finClient logoSeptember 17, 2013Page 5From Andrew Kirkman

2006 - ASTM Guide of LNAPLConceptual Site Models(currently being revised and willbe published in 2014)2009 - ITRC Guide for LNAPLtechnology selection– Defines LNAPL TransmissivityEndpoint range of 0.1 to 0.8ft2/day for Hydraulic RecoveryPublished peer-reviewedefforts to improve LNAPLunderstanding2011 - ASTM Guide forEstimation of LNAPLTransmissivity2012 - API tools and documents– most pertinent here LNAPLbaildown test spreadsheet (inExcel) and guidance document Released October 2012ASTM LNAPL Standard Guide forEstimating LNAPL TransmissivitySeptember 17, 2013Page 6Client logo

ASTM Transmissivity Standard Guide (E2856-11) It establishes standard protocol for conducting tests,evaluating and analyzing To data– Allows for To comparison across sites, between sites and over time Increase accuracy of calculations for To– Aims for an accuracy within a factor of two of actual To Includes four different methods for measuring To in a singleASTM guideline to provide comparison of methods Include methods that are applicable to a variety of geologicconditions (perched, confined, and unconfined) Establish assumptions and limitations of each methodASTM LNAPL Standard Guide forEstimating LNAPL TransmissivitySeptember 17, 2013Page 7Client logo

LNAPL Transmissivity Test Methods Include:Short Term Test MethodsLong Term Test MethodsInstantaneous stress; monitor responseprolonged stress, monitor responseBaildown/SlugTestsManualRecoverySkimming SystemTestData(Zimmerman andLundy, 1995 andHuntley, 2000)ASTM LNAPL Standard Guide forEstimating LNAPL TransmissivityTracerTesting(Sale, 2007)(Charbeneau,2007)September 17, 2013Page 8Client logo

Precautions for Baildown Tests:Short Term Test MethodsBaildown/SlugTests Relatively Mature LNAPLConceptual Site Model (LCSM)ManualSkimmingTestLong Term Test MethodsRecoverySystemDataTracerTesting Well Construction: Well screens need to extend over the entireLNAPL mobile interval Establish that in-well LNAPL thicknesses are at equilibrium: pretest monitoring Well Development: establishes good communication betweenwell and formation Critical Points:– Understand borehole/filter pack recharge – How much do you bail? (up to67% of LNAPL is from the filter pack – e.g., 2” well with 8.25” borehole)– Gauge well to completion of the test not 80%ASTM LNAPL Standard Guide forEstimating LNAPL TransmissivitySeptember 17, 2013Page 9Client logo

Short Term Test Methods1. Baildown TestsBaildown/SlugTestsLong Term Test esting Applicable to:– Aquifer types: confined, unconfined, perched– Developed monitoring well Test method:Qn Vn– Remove single slug of borehole LNAPL (well sand pack)– Monitor LNAPL layer recovery over timeVadosesn bnGroundwater– Cooper-Jacob MethodFilter PackLNAPL Analytical options:– Bouwer-Rice Methodology Not generally applicable to– LNAPL thicknesses 0.5 feetrw– Variable water-table conditions where recharge is longcompared to changes in groundwater elevation.Well radius – adjusted for filterpack porosity and NAPL saturationASTM LNAPL Standard Guide forEstimating LNAPL TransmissivitySeptember 17, 2013Page 10Client logo

Short Term Test MethodsLNAPL Baildown Test Exampleand Initial Data Review ToolsBaildown/SlugTestsManualSkimmingTestLong Term Test MethodsRecoverySystemDataTracerTestingASTM and API provide new tools to understand if the data is ideal or whatcorrections, if any, are appropriateLNAPL Discharge (ft3/d)Time 26.00.3526.527.528.028.50.30Depth (ft)27.00.250.200.1529.00.1029.50.0530.0DTW (blue), Water Table (green), DTP (red)0.0030.5Hydrograph data can help understand variability in thewater-table and consistency of LNAPL recovery trendsLNAPL Drawdown - Discharge RelationWhere equilibrium fluid levels are not well understood,equilibrium fluid level inputs can be adjusted to line the dischargeversus drawdown trend to intersect the origin (0,0).Note how discharge goes to zero as drawdown goes to zeroASTM LNAPL Standard Guide forEstimating LNAPL TransmissivitySeptember 17, 2013LNAPL Drawdown (ft)0.1Page 11Client logo

Short Term Test MethodsAPI Baildown Spreadsheet (2012) Provides tool consistent withASTM methodology to analyzebaildown ystemData2TnEnter early time cut-off for least-squares model fitTimecut0Le/re6.8 - Enter or change value hereModel Results: Tn (ft2 /d) 5.07 /-0.13C1.07R/reft2 /d0100200300-0.1574005000.0-0.5-1.0– Bouwer-Rice– Cooper-Jacob– CP&B-1.5-2.0-2.5-3.0-3.5-4.0Bouwer and Rice ModelSeptember 17, 20133.95J-RatioTime (minutes) 3 Analysis MethodsASTM LNAPL Standard Guide forEstimating LNAPL TransmissivityTracerTestingre ln R re ln sn t1 s n t2 J t t1Page 12Client logoNatural Log of Drawdown (ft)– Helps identify and eliminateborehole recharge– Includes methodology to analyzeconstant discharge portions ofconfined and perched tests– Includes multiple graphs for datainterpretationLong Term Test MethodsCoef. OfVariation0.02

Time 53.01.0B&R Type Curves: Casing Dia. (ft) 0.25 ;Borehole Dia. (ft) 0.420.9T 0.01ft2/day0.80.70.6T 0.05ft2/day0.50.40.3T 0.1 ft2/day0.2T 5 ft2/day0.10.054.0Depth (ft)Normalized Drawdown (s/sinitial) (ft/ft)Baildown Testing API Spreadsheet0T 0.2 ft2/dayT 0.5 ft2/dayT 2 ft2/day1000 2000 3000 4000 5000 6000 7000 8000 9000 10000Time (min)55.056.057.058.059.060.061.062.0DTW (blue), Water Table (green), DTP (red)ASTM LNAPL TransmissivityStandard PreviewSeptember 17, 2013Page 13Client logo

Short Term Test Methods2. Manual Skimming TestBaildown/SlugTestsManualSkimmingTestLong Term Test MethodsRecoverySystemDataTracerTesting Small thicknesses (i.e, 0.5 ft) do not yield good baildowntests due to gauging errors Manual skimming similar timeframe to baildown test Methodology consists of repeated LNAPL removal eventsto reach steady state recovery rate. Recovery rate used in Theim equation along with estimateddrawdown valueQn ln( Roi )TnASTM LNAPL Standard Guide forEstimating LNAPL TransmissivitySeptember 17, 2013rwsClient logo

Short Term Test MethodsManual Skimming TestingManualSkimmingTestBaildown/SlugTestsLong Term Test MethodsRecoverySystemDataTracerTesting Basis – Skimming Recovery Equation Field MethodsTransmissivity (Tn)– Remove Borehole Volume Repeatedly– Establish Sustainable NAPL Discharge Applicability– 0.5 Feet or Rapid Recharge– Minimizes Gauging Errors Equation:Qn ln(TnRoisnrw)Qn ln(bn (1 2010 by H2A Environmental, Ltd., All Rights ReservedASTM LNAPL Standard Guide forEstimating LNAPL TransmissivitySeptember 17, 2013RoiClient logo)rwr)

Short Term Test Methods3. Recovery System DataBaildown/SlugTestsSkimmingWater EnhancedLong Term Test esting Technologies– Water Enhanced Recovery 2010 by H2A Environmental, Ltd.,All Rights ReservedVacuum & Water Extraction(MPE)Trench RecoveryzOW 2010 by H2A Environmental, Ltd.,All Rights ReservedSeptember 17, 2013– Multiphase extraction– Trenches– SkimmingQniPUMPING CONDITIONSzAOzCGWASTM LNAPL Standard Guide forEstimating LNAPL Transmissivity Vacuum enhancedSkimming 2010 by H2A Environmental, Ltd.,All Rights ReservedSTATIC CONDITIONSTransmissivity (Tn) Single or dual pump Equation Development– Charbeneau (2007)Client logo

Short Term Test MethodsShort Term Recovery EvaluationTwrQo2RecoverySystemDataQwLNAPL TransmissivityLNAPL Transmissivity (ft /day)ManualSkimmingTestLNAPL Recovery RateWater Recovery Rate0.5500.4400.3300.2200.1100Dec-06ASTM LNAPL Standard Guide forEstimating LNAPL Transmissivity0Jan-07September 17, 2013Feb-07Mar-07Apr-07Client logoLNAPL Recovery Rate (gpd)Water Recovery Rate (1000 gpd)ToBaildown/SlugTestsLong Term Test MethodsTracerTesting

Short Term Test MethodsLong Term Recovery EvaluationLNAPL Recovery Rate (gpd)Baildown/SlugTestsManualSkimmingTestLong Term Test MethodsRecoverySystemDataLNAPL Transmissivity (ft 2/d)1000100101ToTwrQoQw0.119881990ASTM LNAPL Standard Guide forEstimating LNAPL Transmissivity19921994September 17, 201319961998200020022004Client logo2006TracerTesting

Short Term Test Methods4. Tracer TestingBaildown/SlugTestsLong Term Test esting Can take months BasisTransmissivity (Tn)– Employ Localized Qfand LNAPL gradient– Initially CapitalIntensiveet al Test2007) (SaleField––––Tracer Concentrations (UV/VIS spectrometer)GradientLNAPL Thickness ( 0.2 ft)Well ConstructionASTM LNAPL Standard Guide forEstimating LNAPL TransmissivitySeptember 17, 2013 Analytical Options– Calculate LNAPL flux through well– Calculate LNAPL flux throughformation– Calculate ToClient logo

Scale of LNAPL transmissivity values For example, new catastrophic release scenarios have resulted in LNAPLtransmissivity values on the order of up to 80 ft2/day. Considering the Theim Equation:() To 80 ft2/day with skimming (and assming 1 ft of drawdown), it wouldresult in 816 gpd recovery at start up:– A well would recover 80% of a 700K gallon release within 2 years with 6skimming wells and considering declining recovery Alternatively, assuming an LNAPL To 0.1 ft2/day, skimming ( 0.15 ft ofdrawdown) would result in only 0.2 gpd at start up:– Equal to a total recovery of only 300 gallons in 4 years– Total remaining plume size is 6,400 gallons (so only 5% of plume recovered)– i.e., Hydraulic recovery is not effective in significant plume reductionASTM LNAPL Standard Guide forEstimating LNAPL TransmissivitySeptember 17, 2013Page 20Client logo